Gliederung

The aim of the present study was to show that Angiotensinogen (AGT), which possesses anti-angiogenic property in vitro also exerts inhibitory activities in vivo on the arterial wall. To that end, we measured the thickness of the walls of small and medium size arteries in the kidney of mouse exhibiting different circulating concentrations of AGT. As it was shown in the original study, the wall of arteries of AGT -/- mice (n = 4, 30 vessels/animal) was much thicker than that of AGT +/+ animals (n = 4, 30 vessels/animal). We measured a difference of 39,9 %. More unexpectedly we measured an 19,7 % difference between nude mice that received an adenoviral construction producing high levels of circulating AGT (n = 10, 30 vessels/animal), in comparison to animals which received an empty adenoviral vector (nude mice, n = 10, 30 vessels/animal). A similar difference was measured between the artery wall thickness of AGT -/- mice (n = 4, 30 vessels/animal) compared to the same genotype carrying an angiotensinogen transgene expressed in the adipose tissue (Tg-KO, n = 4, 30 vessels/animal). All differences in wall thickness between controls and AGT exposed arteries were statistically significant (p < 0,01). In these three instances the mere presence of AGT in the blood was sufficient to reduce the arterial wall thickness by 20 to 30 %. It is remarkable that short and long term exposure to AGT lead to a similar reduction in vessel wall thickness. These observations constitute the first quantitative evidence of a growth inhibitory role of AGT on the artery wall in vivo.